Field
This invention relates generally to an antenna subsystem for a communications satellite and, more particularly, to an integrated antenna and RF payload for inter-satellite link communication including a main antenna reflector having a super-elliptical shape and a subreflector, where the subreflector and feed assembly are fixed in position to the satellite, and the main reflector has a single-axis gimbal mount for aiming adjustment in the elevation direction and a wide beam which precludes the need for aiming adjustment in the azimuth direction.
Discussion
Communications satellites are used to enable many different types of telecommunications. For fixed (point-to-point) services, communications satellites provide a microwave radio relay technology which is complementary to that of communication cables. Communications satellites are also used for mobile applications such as communications to ships, vehicles, planes and hand-held terminals, and for TV and radio broadcasting.
In one common implementation, a constellation including dozens of communications satellites are placed in low earth orbit (LEO) or medium earth orbit (MEO) in a constellation which circles the earth. The individual satellites in the constellation communicate with each other, and also communicate with users and communications providers on or near the earth's surface. The communications among the satellites in the constellation are handled by what are known as inter-satellite links (ISL).
There are many factors which provide motivation for cost reduction, mass reduction and simplification in communications satellites—and in the ISL subsystem in particular. These factors include the large number of satellites required in LEO or MEO constellations, the high cost of launching satellites in general and the dramatic effect of mass on cost, and the need for extreme levels of reliability. As a result of all of these factors, there is a need for an ISL subsystem with lower cost, lower mass and simpler operation than ISL subsystems currently used on communications satellites.